Bash, awk, two arguments for one column

Question

Need 2 arguments in awk command for one column.

Script, name todo.

#!/bin/bash

folder_main="$( cd $( dirname "${BASH_SOURCE[0]}" ) >/dev/null 2>&1 && pwd )"

if [ $1 = 'e' ]; then
    mcedit $folder_main/kb/todo.kb
else
    awk -F ',' '$1=="'$1'"' $folder_main/kb/todo.kb
fi

Expectation is when I write todo i, it will grep me lines with i OR c by the first column divided by ,.

I tried this.

    awk -F ',' '$1=="{c|'$1'}"' $folder_main/kb/todo.kb

But nothing.

Thanks.

Ok. Now remove your mail address.

Akina
– Akina

2019-09-06 09:28:43 +00:00
Commented Sep 6, 2019 at 9:28 — Akina
– Akina, Commented Sep 6, 2019 at 9:28

Tom Fenech · Accepted Answer · 2019-08-07 14:19:16Z

2

You should pass your shell variable to awk using -v and fix your awk syntax:

awk -F, -v a="$1" '$1 == "c" || $1 == a' "$folder_main/kb/todo.kb"

This sets the awk variable a to the value of the shell positional parameter $1, and prints the line if the first column is either "c" or whatever you passed as the first argument to the script.

You could also shorten the line slightly by using a regular expression match instead of two ==:

awk -F, -v a="$1" '$1 ~ "^(c|"a")$"' "$folder_main/kb/todo.kb"

Although I think that the first option is easier to read, personally. It is also safer to use, as a character with special meaning inside a regular expression (such as *, [, ( or {) could cause the script to either fail or behave in an unexpected way.

edited Aug 7, 2019 at 14:19

answered Aug 7, 2019 at 13:23

Tom Fenech

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Comments

JNevill · Accepted Answer · 2019-08-07 13:21:34Z

0

You can't use shell variables directly in awk like this. Instead you pass them into your awk script using the -v flag:

awk -F ',' -v searchterm=$1 '$1==searchterm' $folder_main/kb/todo.kb

answered Aug 7, 2019 at 13:21

JNevill

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2 Comments

genderbee Over a year ago

OK, but my first example works ok too. But your solution is more elegant. And what about 2 searchterms with OR? I tried searchterm={"$1"|"c"}, but false. Thanks.

JNevill Over a year ago

Take a look at the other answer. That does similar to what I've done but performs the search using regex which is more elegant for your OR requirements.

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